Place 2 beer bottles (brand of your choice) on the ground (recommend to do this outside). Draw a circle with an 18" radius around each bottle.

During a night of heavy drinking, have your team piss into the other teams bottle from outside the 18 inch radius. Whomever fills the other teams bottle first is the winner! The loser gives the rest of their beer to the winners. So you had better be a good accurate pisser.